System and Network Administration Overview (Linux in a Nutshell, 3rd Edition)

2.1. Common Commands

Following are lists of commonly used system administration commands.

2.1.1. Clocks

hwclock	Manage hardware clock.
netdate	Set clock according to host's clock.
rdate	Manage time server.
zdump	Print list of time zones.
zic	Create time conversion information files.

2.1.2. Daemons

apmd	Advanced Power Management daemon.
bootpd	Internet Boot Protocol daemon.
fingerd	Finger daemon.
ftpd	File Transfer Protocol daemon.
gated	Manage routing tables between networks.
identd	Identify user running TCP/IP process.
imapd	IMAP mailbox server daemon.
inetd	Internet services daemon.
kerneld	Provide automatic kernel module loading.
klogd	Manage syslogd.
lpd	Printer daemon.
mountd	NFS mount request server.
named	Internet domain name server.
nfsd	NFS daemon.
pop2d	POP server.
pop3d	POP server.
powerd	Monitor UPS connection.
pppd	Maintain Point-to-Point Protocol (PPP) network connections.
rdistd	Remote file distribution server.
rexecd	Remote execution server.
rlogind	rlogin server.
routed	Routing daemon.
rshd	Remote shell server.
rwhod	Remote who server.
syslogd	System logging daemon.
talkd	Talk daemon.
tcpd	TCP network daemon.
tftpd	Trivial File Transfer Protocol daemon.
update	Buffer flush daemon.
ypbind	NIS binder process.
yppasswdd	NIS password modification server.
ypserv	NIS server process.

2.1.3. Hardware

agetty	Start user session at terminal.
arp	Manage the ARP cache.
cardctl	Control PCMCIA cards.
cardmgr	PCMCIA card manager daemon.
cfdisk	Maintain disk partitions (graphical interface).
fdisk	Maintain disk partitions.
getty	Start user session at terminal.
kbdrate	Manage the keyboard's repeat rate.
ramsize	Print information about RAM disk.
setserial	Set serial port information.
slattach	Attach serial lines as network interfaces.

2.1.4. Host Information

arch	Print machine architecture.
dnsdomainname	Print DNS domain name.
domainname	Print NIS domain name.
free	Print memory usage.
host	Print host and zone information.
hostname	Print or set hostname.
nslookup	Query Internet domain name servers.
uname	Print host information.

2.1.5. Installation

cpio	Copy file archives.
install	Copy files into locations providing user access and set permissions.
rdist	Distribute files to remote systems.
tar	Copy files to or restore files from an archive medium.

2.1.6. Mail

fetchmail	Retrieve mail from remote servers.
formail	Convert input to mail format.
mailq	Print a summary of the mail queue.
makemap	Update sendmail's database maps.
rmail	Handle uucp mail.
sendmail	Send and receive mail.

2.1.7. Managing Filesystems

To Unix systems, a filesystem is some device (such as a hard drive, floppy, or CD-ROM) that is formatted to store files. Filesystems can be found on hard drives, floppies, CD-ROMs, or other storage media that permit random access.

The exact format and means by which the files are stored are not important; the system provides a common interface for all filesystem types that it recognizes. Under Linux, filesystem types include the Second Extended Filesystem, or ext2fs, which you probably use to store Linux files. The second extended filesystem was developed primarily for Linux and supports 256-character filenames, 4-terabyte maximum filesystem size, and other useful features. (It is "second" because it is the successor to the extended filesystem type.) Other common filesystem types include the MS-DOS filesystem, which allows files on MS-DOS partitions and floppies to be accessed under Linux, and the ISO 9660 filesystem used by CD-ROMs.

debugfs	Debug extfs filesystem.
dosfsck	Check and repair a DOS or VFAT filesystem.
dumpe2fs	Print information about superblock and blocks group.
e2fsck	Check and repair a second extended filesystem.
fdformat	Format floppy disk.
fsck	Check and repair filesystem.
fsck.minix	Check and repair a MINIX filesystem.
fuser	List processes using a filesystem.
mke2fs	Make new second extended filesystem.
mkfs	Make new filesystem.
mkfs.ext2	Another name for mke2fs.
mkfs.minix	Make new MINIX filesystem.
mklost+found	Make lost+found directory.
mkraid	Set up a RAID device.
mkswap	Designate swap space.
mount	Mount a filesystem.
raidstart	Activate a RAID device.
raidstop	Turn off a RAID device.
rdev	Describe or change values for root filesystem.
rootflags	List or set flags to use in mounting root filesystem.
showmount	List exported directories.
swapdev	Display or set swap device information.
swapoff	Cease using device for swapping.
swapon	Begin using device for swapping.
sync	Write filesystem buffers to disk.
tune2fs	Manage second extended filesystem.
umount	Unmount a filesystem.

2.1.8. Managing the Kernel

depmod	Create module dependency listing.
insmod	Install new kernel module.
lsmod	List kernel modules.
modprobe	Load new module and its dependent modules.
rmmod	Remove module.

2.1.9. Networking

dip	Establish dial-up IP connections.
gdc	Administer gated routing daemon.
ifconfig	Manage network interfaces.
ipchains	Administer firewall facilities (2.2 kernel).
iptables	Administer firewall facilities (2.4 kernel).
named	Translate between domain names and IP addresses.
netstat	Print network status.
portmap	Map daemons to ports.
rarp	Manage RARP table.
route	Manage routing tables.
routed	Dynamically keep routing tables up-to-date.
rpcinfo	Report RPC information.
ruptime	Check how long remote system has been up.
rwho	Show who is logged in to remote system.
systat	Show status of remote systems.
traceroute	Trace network route to remote host.

2.1.10. NIS Administration

domainname	Set or display name of current NIS domain.
makedbm	Rebuild NIS databases.
ypbind	Connect to NIS server.
ypcat	Print values in NIS database.
ypchfn	Change user information in NIS database for finger, email, etc.
ypchsh	Change user login shell in NIS database.
ypinit	Build new NIS databases.
ypmatch	Print value of one or more NIS keys.
yppasswd	Change user password in NIS database.
yppasswdd	Update NIS database in response to yppasswd.
yppoll	Determine version of NIS map at NIS server.
yppush	Propagate NIS map.
ypserv	NIS server daemon.
ypset	Point ypbind at a specific server.
ypwhich	Display name of NIS server or map master.
ypxfr	Transfer NIS database from server to local host.

2.1.11. Printing

lpc	Control line printer.
tunelp	Tune the printer parameters.

2.1.12. Security and System Integrity

badblocks	Search for bad blocks.
chroot	Change root directory.

2.1.13. Starting and Stopping the System

bootpd	Internet Boot Protocol daemon.
bootpgw	Internet Boot Protocol gateway.
bootptest	Test bootpd.
halt	Stop or shut down system.
init	Change runlevel.
reboot	Shut down, then reboot system.
runlevel	Print system runlevel.
shutdown	Shut down system.
telinit	Change the current runlevel.
uptime	Display uptimes of local machines.

2.1.14. System Activity and Process Management

A number of additional commands in Chapter 3, "Linux Commands", are particularly useful in controlling processes, including kill, killall, killall5, pidof, ps, and who.

fuser	Identify processes using file or filesystem.
psupdate	Update /boot/psupdate.
renice	Change the priority of running processes.
top	Show most CPU-intensive processes.

2.1.15. Users

chpasswd	Change multiple passwords.
groupadd	Add a new group.
groupdel	Delete a group
groupmod	Modify groups.
grpck	Check the integrity of group system files.
grpconv	Convert group file to shadow group file.
lastlog	Generate report of last user login times.
newusers	Add new users in a batch.
pwck	Check the integrity of password system files.
pwconv	Convert password file to shadow passwords.
rusers	Print who-style information on remote machines.
rwall	Print a message to remote users.
useradd	Add a new user.
userdel	Delete a user and her home directory.
usermod	Modify a user's information.
w	List logged-in users.
wall	Write to all users.
whoami	Show how you are currently logged in.

2.1.16. Miscellaneous

cron	Schedule commands for specific times.
dmesg	Print bootup messages after the system is up.
ldconfig	Update library links and do caching.
logger	Send messages to the system logger.
logrotate	Compress and rotate system logs.
rstat	Display host's system status.
run-parts	Run all scripts in a directory.

Chapter 2. System and Network Administration Overview

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